EXERCISE 8-3. INCREASED ABDOMINAL DENSITY OR MASSES
8-9. What is the most likely diagnosis of this soft-tissue mass (arrows) in Case 8-9 (Figure 8-18)?
8-10. What is the most likely diagnosis of this soft-tissue mass (arrows) in Case 8-10 (Figure 8-19)?
A. Adrenal carcinoma
B. Gastric outlet obstruction
C. Renal cell carcinoma
8-11. What is the most likely diagnosis of this soft-tissue mass (arrows) in Case 8-11 (Figure 8-20)?
A. A pseudotumor sign of small bowel obstruction
B. Gastric outlet obstruction
D. Horseshoe kidney
8-12. What is the most likely diagnosis in Case 8-12 (Figure8-21)?
A. Ovarian cyst
B. Pelvic abscess
C. Pelvic hematoma
D. Pelvic kidney
8-9. In this case, the right side of the abdomen shows increased density and is relatively free of gas. Displacement of the gas pattern in the duodenum and jejunum to the left side is indicative of hepatomegaly (C is the correct answer to Question 8-9). Hepatic metastases from lung cancer were later confirmed.
8-10. In this case, a soft-tissue mass in the left upper quad-rant displaces the gas in the splenic flexure of the colon downward. Left adrenal or renal cell carcinoma rarely presents as a large mass to the left of the mid-line. The most likely diagnosis is splenomegaly (D is the correct answer to Question 8-10).
8-11. In this case, a mass in the midabdomen delineates the lower poles of both kidneys, which are fused at the midline, consistent with horseshoe kidney (D is the correct answer to Question 8-11). Small renal cal-culi (arrowheads) are present bilaterally.
8-12. This case shows a soft-tissue mass in the pelvis. In a middle-aged woman, an ovarian or uterine mass would be the most likely considerations. Ultrasonog-raphy of the pelvis showed a large, fluid-filled mass, confirmed surgically as an ovarian cyst (A is the cor-rect answer to Question 8-12).
Although abdominal plain radiographs are useful in detecting hepatomegaly or splenomegaly, they are of little use in diag-nosing hepatic disease, particularly if hepatomegaly is not present. Other imaging modalities, such as ultrasonography, CT (Figures 8-22, 8-23), MR imaging, and radionuclide liver scans, are more sensitive and accurate for evaluating hepatic primary diseases or metastases. In addition, barium studies of the gastrointestinal tract and CT may be helpful in excluding gastric outlet obstruction, carcinoma, or renal cell carcinoma.
Fusion of the kidneys may occur in the embryologic stage during the second month of gestation. Most (95%) of these fusions occur at the lower poles of the kidneys. CT shows the kidney to be vertical or even in the reverse oblique directionand its position to be lower than normal. Horseshoe kidney may be associated with other congenital anomalies, as well as a high incidence of urinary tract obstruction, infection, or stone formation. A horseshoe kidney may also deviate the upper ureters laterally.
When the plain film suggests the presence of a pelvic mass, a specific diagnosis is often not possible. Pelvic ultra-sonography, CT (Figure 8-24), or MR imaging better demon-strates the pelvic organs and their interrelationship and will differentiate between solid and fluid content in the mass.